2-Fluoromorphine has been prepared for study of its analgesic action and receptor-binding ability, in comparison with those of the 1-fluoro isomer. Synthesis of codeine and/or 1-fluorocodeine from precursors suitably blocked to prevent formation of undesired products is being investigated. The structure of a long-known anomalous demethylation product of 5-benzyldihydromorphinone has been elucidated. The color dimorphism of 14-hydroxymorphinone has been studied; it is connected with different intermolecular hydrogen-bonding in the colorless and yellow forms, respectively. Tetramethyl cis-bicyclo(3.3.0)octane-3,7-dione 2,4,6,8-tetracarboxylate loses the carbomethoxyls at C-4 and C-8 almost quantitatively on mild treatment with NaOMe in DMSO-MeOH. Tricyclo(6.3.0.0.1,5)undecane-3,7,9-trione, derived from a little-known, conformationally rigid ring system, has been synthesized. These cyclopentanoid compounds might be valuable intermediates in the synthesis of pharmaca. Reaction of dimethyl 3-ketoglutarate with glyoxal and guanidine did not yield the expected derivative of cyclopentano-4,5-imidazolidine. Lachnanthocarpone, a 9-phenylphenalenone pigment from Lachnanthes tinctoria (Haemodoraceae) has been synthesized by spontaneous intramolecular Diels-Adler reaction of a suitable orthoquinonoid 1,7-diarylheptadiene. BIBLIOGRAPHIC REFERENCES: Yang-Lan, S., Mueller-Johnson, M., Oehldrich, J., Wichman, D., Cook, J.M. and Weiss, U.: Reaction of dicarbonyl compounds with dimethyl beta-ketoglutarate. 4. Formation of 1:1 adducts. J. Org. Chem. 41: 4053-4058, 1976. Bazan, A.C., Edwards, J.M. and Weiss, U.: Synthesis of lachnanthocarpone (9-phenyl-2,6-dihydroxyphenalen-1(6)-one) by intramolecular Diels-Adler reaction of a 1,7-diarylheptadienoid intermediate. Tetrahedron Letters: 147-150, 1977.